


Tangled String

by captain_shitpost



Category: Undertale (Video Game)
Genre: Alternate Universe - Underfell, Amputation, Ecto-Genitalia (Undertale), Established Relationship, Everyone Acts Edgier Than They Really Are, Fluff, Fontcest, Genocide, Healthy Communication, Healthy Relationships, Hurt/Comfort, Incest, Kedgeup, M/M, Mating Cycles/In Heat, Mostly Idea Exploration Rather Than Plot, Multi, Non-Binary Frisk, Polyamory, Polyamory Negotiations, Post-Traumatic Stress Disorder - PTSD, Sexuality Before First Heat, Sibling Incest, Slice of Life, Smut, Soul Sex, Suicidal Thoughts, Underfell Papyrus, Underfell Sans, Underfell fontcest - Freeform, kustard - Freeform
Language: English
Status: In-Progress
Published: 2017-04-17
Updated: 2017-04-22
Packaged: 2018-10-20 03:44:10
Rating: Explicit
Warnings: Graphic Depictions Of Violence
Chapters: 2
Words: 6,779
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/10654206
Author URL: https://archiveofourown.org/users/captain_shitpost/pseuds/captain_shitpost
Summary: Sans has given up. After his fight with the Anomaly, he knew it was only a matter of time before he dusted, and could you blame him for wanting to be with someone he knew in his last moments? But when he took a shortcut to Grillby's, something went wrong and flung him to a new world-one where it's kill, or be killed. His brother is alive but completely different, and a different version of him enjoys pissing him off.For some reason, they both help him get better again. With their help he may just learn to live again, as long as he lets them in. After all, that's a lot easier said than done.UPDATES VERY IRREGULARLY.





	1. Welcome to Underfell

Sans was having an oddly good day. He got up this morning to Boss calling him a lazy fuck and kicking him out of bed, ate an admittedly dubious breakfast of bread and mustard, took a nice long nap at his sentry station, scammed a few people out of their money selling shitty hotdogs and eventually wandered over to Grillby’s. Almost 2 hours later, he was pleasantly buzzed and waiting for his brother to burst through the doors in exactly 37 minutes and drag him home when he felt a tingle near the base of his spine, followed by the sound of a large object crashing behind him and breaking wood. He whipped around and saw a previously empty bar table smashed into splinters, the monsters that were near it scrambling away to safety.

The entire bar was completely silent for probably the first time since it opened. It lasted all of 10 seconds until the crowd erupted into activity.

Everyone was scuffling, either trying to back away from the table or trying to approach it out of curiosity. With the entire guard out on duty, the patrons were getting rowdy, right up until Grillby slammed the glass he was cleaning hard on the counter, crackling in warning. Nobody was stupid enough to challenge the bartender’s authority, so once he flicked his hand everybody backed away from the rubble. He approached it, fireball ready to fly in hand, and Sans quietly followed him, right behind his billowing coattails.

He saw the way Grillby stopped and straightened out, the minute stutter of his flames giving away his surprise. He shuffled next to the taller monster to get a better look, and holy shit it was a skeleton.

A rather unusual skeleton, though Sans had little experience with his own kind. They were strangely short (he had been sure he was the only short skeleton to ever exist until now), wearing a hoodie in a rare shade of blue and slippers. _Slippers_. They had a style that Sans could appreciate, even if they didn’t have common sense. And he saw all that before he noticed the stream of dust falling out of their sleeve.

Grillby was fast on his feet, bending down to pull the skeleton’s hoodie off, Sans feeling a rising sense of nausea when he saw the way their arm was slowly dusting, the decay creeping up to their elbow. Grillby frowned.

“…Whiskey,” he barked out, Red Bird jumping off their barstool and looking for the requested item. The fireball Grillby summoned changed colours from purple to green and he quickly pressed it into their chest. Sans approached the skeleton’s head, trying to see if they were awake.

He saw that their- _his_ eyelids were closed, just like Sans expected from his lack of reaction. What he didn’t expect was his face being a mirror image of his own, except his teeth were blunt and all accounted for, and he had no scars on his face.

Shit. He knew who this was. He knew who this was and he knew why they were dusting so slowly, despite not being a boss monster. His eyes flickered to the skeleton’s ribs and he was unsettled by the deep gash running across them diagonally, visible through the tatters of his shirt, starting from his right clavicle and cutting left to the bottom of his ribs. A red liquid was pooling from it, dripping slowly down his ribs, soaking into his clothes.

He was pushed aside by Red Bird so he could put the whiskey down next to Grillby. Sans backed off to let them work and pulled out his cellphone, letting out a relieved breath when he saw the battery wasn’t dead.

“grillbz, i’m calling boss. he’s gonna want to know about this,” he announced, dialing the number and listening to the annoying beeping. Grillby barely had time to nod, frown of concentration on his face, before Boss answered.

“SANS I SWEAR TO GOD IF YOU FORGOT YOUR MONEY BEFORE EATING AT GRILLBY’S AGAIN I’M GOING TO THROW YOU OUT THE WINDOW.”

Sans grimaced. Calling his brother to annoy him and consequently get nagged at was usually the highlight of his day, despite Papyrus limiting it to once a day to prevent slacking off during work hours, and this was definitely not what he wanted to talk to his bro about. “uh. didn’t, actually. there’s kinda a situation at grillby’s. can you send in one of the guards?”

He heard Boss’ huff on the other end. “NO, THEY ALL HAVE TRAINING WITH UNDYNE TODAY, I’M COVERING FOR THEM. I’LL BE THERE IN A MINUTE,” he exclaimed, the sound of snow crunching loudly audible from the speaker. “WHAT IS THE SITUATION?”

Red looked around, checking to see if all the other monsters’ attentions were on the passed-out skeleton and bartender, then quietly slipped out the door. “a monster fell into grillby’s table. he’s, uh, pretty messed up,” he muttered, swallowing nervously. “fell, as in fell out of thin air. grillbz is trying to keep him alive.”

There was a pause on the other side in which Sans heard only breathing and running. “WHAT DO YOU MEAN, FELL OUT OF THIN AIR? LIKE A SHORTCUT? YOU SAID ONLY YOU COULD DO THAT,” he exclaimed. Red could see a dot in the distance, approaching Snowdin from the forest, kicking up snow as it moved.

“ho boy. listen, bro,” he said, knowing it sounded more personal than Boss, “this is gonna be really weird and i promise i’ll try to explain after we’re alone, but once you get here you gotta make sure the guy stays with us, alright? at least at first.”

The dot was covering a lot of ground, and soon he could see the red scarf billowing behind it. He turned off his phone and stuck it in his pocket along with his hands. He always fidgeted with them when he was nervous, and showing your nerves was a sign of lack of control over emotions. A vulnerability.

Slowing down from his mad dash yet not breaking a sweat, Papyrus stopped in front of him. Sans let out a breath of relief he didn’t realize he was holding as the other skeleton straightened out, scapulas rolled back and chin up, looking every bit the vice-captain of the Royal Guard. Stars, his brother was cool.

He leveled his eye light at Sans, making him subconsciously straighten up. It was a purely professional look, so he responded in kind. “SHOW ME.”

Sans stepped into the bar, stepping to the side and holding the door open for Boss. His boots made an intimidating ‘click, click’ on the wooden floor, and all the monsters’ gazes, except Grillby’s, snapped to him. It was ballsy, making so much noise when you walked. It showed you were confident enough you didn’t need to hide.

They approached the passed-out skeleton, watching as Grillby tried to get him to choke down some whiskey to heal him, apparently hitting the limit of what green magic could do. He saw Boss stop for a moment, a flash of surprise showing on his face, but he snuffed it out before anyone else noticed.

“WHAT’S HIS STATUS?” Papyrus demanded.

“Dead, if you don’t fuck off and let me work,” Grillby snapped back. He was probably the only monster in Snowdin that could get away with blatant disrespect of that level, but given that he was usually cooperative with the demands of the Guard, Boss let it slide this time. There was a mutual dislike yet grudging respect between the two monsters, and Sans figured that if it had been anyone else that talked to him that way they would be eating their teeth.

With a grumble, Papyrus stepped back and turned to the bar patrons, barking out demands and questions at the shaky, half-drunk monsters to gather information. He wouldn’t be getting a lot, but Sans knew his brother would have to write a report about this later.

Grillby suddenly gestured him over, so Sans followed his non-verbal instructions, propping the skeleton up so Grillby could force liquid down his throat. The first few tries ended with the whiskey simply dripping through his thoracic opening and down his chest, but after two more rounds of healing magic the passed-out skeleton managed to reflexively convert the substance into magic. The toughest step done, Grillby’s posture relaxed a bit as he fed the skeleton more alcohol.

Sans looked around at the patrons. Papyrus was keeping them busy with interrogations, and Grillby wasn’t the nosy type, so he quickly checked the monster.

***SANS 1 HP 1 ATK 1 DEF**

***1 LV 0 EXP**

***He** **’s given up.**

 

Sans winced. He had a strong hunch already that, _somehow_ , this was a Sans from an alternate universe. Even if his name wasn’t evidence enough, the horrible HP was. But what really unsettled him was this Sans’ lack of EXP-not only was it extremely rare for adults to not have a single LV, but this Sans had obviously been in a fight to the death. Never killed someone, was in a fight to the death, and looking at his flavor text…it painted an unsettling picture. He wondered what happened to him.

“His HP isn’t rising above 1, I can’t help him more than this,” Grillby huffed, putting the bottle away. He knew the fire monster’s posture meant he gave up on his counterpart, but Sans knew that his HP wouldn’t rise above that with healing magic and food. Grillby got up and dusted himself off, then went to collect the splinters of wood that used to be a table off the floor, breaking them into smaller bits and munching on them as he went to get his cleaning supplies.

Papyrus noticed the healing had stopped, so he interrupted the stuttering of the drunk fish monster in front of him and approached. He looked at Sans’ imploring gaze, then picked up the monster, acting cold but carefully cradling his neck, hand underneath his hoodie so nobody could see.

“WE’RE KEEPING HIM DETAINED IN THE SHED UNTIL HE WAKES UP, I CAN’T RISK HIM DUSTING ON THE WAY TO THE NEW HOME JAIL. WE’RE LEAVING. DON’T START SHIT WHILE I’M GONE,” he bit out at the patrons. They nodded stiffly.

Sans grinned a bit more genuinely as he followed him out the door and into the snow, taking his usual position on his brother’s left side and slightly behind him, around an arm’s length away. He carelessly waved behind him to the bartender, and with a ringing the door closed behind them.

Papyrus shifted the skeleton from a bridal carry into a more comfortable position, keeping him propped up on his hip and his skull resting on his shoulder. Sans payed careful attention to the skeleton in case he woke up and tried to attack. He felt the slightest bit of irrational jealousy that he tried to smother. His brother had never carried him in public like that.

It was always nice to see the way Papyrus relaxed once he entered their home (or shed, in this case), when he was finally out of the eye of the public. His posture was still great, but his shoulders weren’t so tense and his spine slouched into something approaching natural. He approached the bed in the corner, well-made in case Captain Undyne needed a place to crash, and set the skeleton on it. Looking over his clothes, he removed the tattered shirt, having to rip it up to get it off completely, then lowered the skeleton’s shorts slightly to check for underwear. His counterpart must have been as lazy as he was, because he wasn’t wearing any, so Papyrus let them be. His fuzzy slippers came off next and then, with a slight blush that made Sans snort and laugh, Papyrus tried removing his socks.

The right one came off easily and landed on the ground with a wet slap, but when Papyrus tugged off the other one, Sans flinched seeing it squish together, like there was no bone to fill it up. Sure enough, it was half-full of dust, and Papyrus spilled the contents on the floor with a curse after he lost his grip on it. Half the skeleton’s foot was gone, all his fingers and metatarsals were missing, as well as all the bones up to the calcaneus. Papyrus clicked his tongue in disgust and left the room, Sans moving closer to continue the examination.

The skeleton’s left foot was half-dusted, and looking carefully he noticed his right foot was missing the very tips of his top phalanges. Checking the rest of his legs and spine, he saw no wounds and was surprised by the utter lack of scars. Even with 1 HP, there were ways of getting wounds without dusting. So no EXP, no previous injuries, but still somehow in a battle to the death. Sans was finding more questions the more he looked for answers.

His right arm was fine, but the left was missing his entire forearm and the bottom part of his humerus. Sans grimaced. If his counterpart was left-handed like him, that would be a bitch to get used to. He saw the giant gash on his otherwise pristine ribs, and noted that while it still looked new and ready to open again if put under strain, it was scabbed over. His skull was in good shape, and he lifted the lids to see his eye lights flicker weakly into life, blown completely and hazy at the edges, indicating that the skeleton would be out for a while.

His brother came back into the room with a first aid kit and cleaning supplies in his hands, carefully proceeding to clean the area around the wound so he could dress it.

“So,” Papyrus said calmly, much quieter once he didn’t have to intimidate random citizens and careful not to disturb their new guest. “What really happened, Sans?”

Sans watched the way his brother’s long fingers unwound gauze, winding it around the smaller skeleton’s ribs. Where the hell should he even start? “remember when i told you about when i was a scientist?”

Papyrus frowned, securing the gauze with pins. “Of course. It was the first damn time I managed to get you to be honest about anything,” he snipped, squeezing out a washcloth to wipe the dust and red liquid off his counterpart’s bones.

“shit, you’ll never let that go, will ya bro?” Sans snickered. “one of the ideas we worked with was parallel universes. like, apart from our own, there are an infinite number of universes out there. and they’re all different. like, some will be completely different from ours, but some will be similar, just with a few changes.”

Papyrus hummed in thought, frowning at how dirty the water got once he put the cloth in. “So it could be a world like ours, but the monsters are on the surface.”

Sans grinned. Damn his bro was smart. “exactly. or it could be a world where monsters don’t even exist, or never even got trapped underground. hell, there could be one that was exactly the same as ours, except the only difference was that i sold 10 hotdogs instead of 11 today.”

“For fuck’s sake, Sans, I told you that’s illegal. You’ll lose your damn job if they catch you at best, jail time at worst, you bonehead,” Papyrus growled, trying his best to stay quiet.

“hey, it’ll be fine, no need to worry. i know a guy, so i won’t get _boned_ ,” Sans said with a smirk, letting Papyrus fume on his own. “but as I was saying, this guy here is probably from one of those other universes. did you try checking him?”

Papyrus dropped the cloth in its basin, the water a disgusting mixture of grey and red. Sans could tell the exact moment he checked, because his expression changed from its default tired annoyance into a look of surprise, the frown deepening as his sockets widened. “Wait, what the-”

“yup. he’s me from another world. i’m not sure how the fuck he got here or why, and i can’t tell yet how dangerous he is. but we should keep an eye on him until he wakes up and i can ask him a few questions. and we’ll see after that. he could cause a mess if he wakes up and has no idea where he is,” Sans explained, looking at his counterpart’s face. During his research, they found evidence of other universes, but they never figured out a way to access them. By all calculations, it was impossible to contact them, so how in the hell did this guy end up here?

Papyrus’ expression shifted into something more somber. “So he’s you? You from another world?” he asked quietly, and if it was anyone else but Sans listening they wouldn’t be able to hear the note of sadness in his voice. Sans gently took his hand, rubbing it with his thumb. He knew exactly what his brother was thinking. He could already see the way his brother was planning their next meals to accommodate the small skeleton’s needs, and the way his eye light flickered over him he knew he was sizing him up for new clothes. For all his bravado, his brother could be such a bleeding heart sometimes.

Sans raised his brother’s hand and clacked the back of his phalanges with his teeth, more of an idea of a kiss than an actual one, but his brother smiled at it anyway. “hey. grillbz did what he could, there’s nothing else we can do for him. he’s gotta pull through on his own,” he mumbled into his brother’s long phalanges, then lowered his hand. He still didn’t let go, though. “come on, get some food and go sleep. i’ll keep an eye on him in case he wakes up.”

Papyrus scoffed. “You’ll fall asleep after five minutes, Sans, I know what you’re like in the evening. You go first, I need to clean up the floor anyways. Take time off tomorrow to keep an eye on him during the day, for once you have an almost decent excuse to skip.”

Sans chuckled, getting up to stand in front of his bro, then bending forward and giving his brother a quick clack on the teeth. “you’re the coolest, bro,” he whispered, his voice going low and full of awe the way he knew made Papyrus blush. Papyrus chuckled deeply and pulled him closer by the hips, wrapping his long arms around his body.

“Of course. After all, I am the Great and Terrible Papyrus! Everything I do is the coolest!” he said half-laughing, before going in for a second kiss, this one much longer. Sans felt his magic spark, and he opened his mouth with a smile when he felt Papyrus’ tongue lick for entrance.

He stood there for a while enjoying the languid yet skilled movements of his brother’s tongue, the way their magic sparked and ebbed at the point of contact, spreading into his bones. He felt the responding heat in his pelvis, but he knew with their unexpected guest needing attention nothing more would happen tonight. All the same, once they broke the kiss he was reluctant to move again, enjoying the way Papyrus nuzzled his skull into the side of his neck, shivering when he let out a warm, content sigh, way too much like the one his brother made in…other situations. He suddenly _really_ regretted his counterpart’s appearance.

With an embarrassed chuckle and a blush, Sans backed up, watching the knowing smirk on his brother’s face. The bastard knew exactly what he was doing.

Payprus smacked him on the ass, laughing loudly at Sans’ yelp of surprise. “Go sleep, brother. I have this covered.”

Sans grumbled, rubbing his ass. His sacrum stung, and it did nothing to kill his arousal. “asshole. we’ll see who’s laughing when i spank _you_.”

Papyrus grinned, too cheeky to really sell the look of fake innocence. “Is that a promise?”

Sans flipped him off with a laugh, then entered the living room through the door that connected it to the shed. It was a new edition, Papyrus nagging him to make it after Undyne bitched about having to walk in the snow to get to the kitchen. The things he did for his brother.

He grabbed the bag of leftover popato chisps from the fridge for his before-bedtime snack, then took a shortcut to his bed, chucking off his sweater and shoes and crawling under the covers. He knew if he ate in Papyrus’ bed he’d get crumbs all over it, and while he gave precisely zero fucks, Papyrus would have a nervous breakdown.

He listened to the sounds of his brother cleaning downstairs as he ate, calming him down until his eyelids were drooping. He didn’t know what happened to his counterpart, or what would happen next, but he knew the routine he had with his brother was going to get blown to shit. It will be such a pain keeping an eye on the guy, if he even survived.

In the very depths of his soul, he felt a pang of worry for the short skeleton. He scoffed and tried to ignore it, but it wouldn’t let go. He let it carry him into an uneasy sleep.


	2. How do I shame the Anomaly for killing everyone?

**Summary for the Chapter:**

> Sans isn't coherent enough to talk things out, but he's coherent enough to hurt.

 “welp. i'm going to grillby's,” Sans choked out, liquid filling his mouth, coating his tongue with the taste of metal and memories. He could feel it running out between his teeth, dribbling down his chin. He couldn’t feel his legs anymore, though. “papyrus, do you want anything?”

His ear holes were buzzing, but he still heard the human’s (the child’s, the anomaly’s-) footsteps echo off the walls. The human didn’t even seem happy once it hit him after countless failed attempts. Its creepy smile just widened a bit more in satisfaction and then it was as empty as it ever was.

He wondered if they had ever been friends, once upon a reset.

His left hand felt numb, his arm on that side suddenly feeling lighter, and looking down he couldn’t see his fingertips sticking out of his sleeve anymore, only the light trickling of dust. Then with a shudder of his magic, his eye lights sputtered out too. He felt like this would be an appropriate time to chuckle bitterly, but the sound stayed stuck in his throat, drowning in the liquid that wouldn’t stay in his body. He hacked it out with a disgusting, wet cough and spit it on the floor. At least when he died he left more of a mark than just dust.

He kept walking to the doorway the human came through, slow and shaky since he couldn’t feel his feet anymore. If he was careless he’d stumble and fall, and he knew he wouldn’t get up again. He just-he didn’t want to be alone. Not now. After all the things he went through the fact that anything still bothered him was ridiculous, but he didn’t want to die alone. He knew Grillby was still holed up in the back of his bar instead of evacuating. It wouldn’t save him when the human destroyed this timeline, but it was company. Warmth and familiarity, when he knew he wouldn’t live to feel it again. He angled himself just right, feeling the link of two rooms joining in a shortcut, and stumbled just as he entered.

He felt a strange shimmering sensation, like light suddenly turned tangible then turned off, and whatever it was it threw off his calculations, so instead of collapsing gently on the floor he felt the whish of air around his skull before he smacked rather dramatically into a bar table. He felt a vague, unpleasant pressure on his back where he hit the wood, his overall numbness sparing him from the pain. He only vaguely saw the dim lights overhead and shapes moving, yelling things he could no longer follow but still comforting in their mere presence. It sounded like multiple voices. Was Grillby’s full? Maybe he’d grab some food while he was here.

Wait. He didn’t come here to eat. Why did he come here again?

Oh, right. The human killed him, he wouldn’t survive long enough to eat. Why were there so many voices here anyway? Did it reset?

Finally. Now he’ll see Papyrus again.

 

He felt himself float in and out of consciousness for what felt like a lifetime, only catching glimpses of movement or garbled noises before he went back under. This time, he felt himself drift into consciousness and instead of going back to sleep he latched onto the sensation, trying to stay awake. He tried to move his fingers and when he couldn’t he blinked open his sockets with a low groan. It took several rapid blinks until his vision focused, his sight going from only blurred outlines to normal detail.

He could make out the grain of the wooden ceiling, and it took him a few moments to remember through his mental fog that his room didn’t have a plain wooden ceiling. So that meant he wasn’t in his room. Where was he? He tried to sit up but yelped as a burning pain seared through his ribcage, making him collapse back into the bed. He panted lightly, trying to suck in air while moving his ribs as little as possible. It was a while before the pain faded into a bright throbbing, making his entire body ache.

He moved his shoulders carefully and winced. Moving them hurt, but if he tried to keep them still he might be able to move his hands. He tried to slowly reach for the blanket covering him, instinctively using his left hand, but his movement was off. His swing was unexpectedly quick, as if his arm got lighter-

He blinked at the stump of his humerus, his entire forearm missing. Well. That was new. With a shaking right hand, he tugged the blanket down, forcing his breath to slow before he had a panic attack. This was really weird, but a reset was coming and then he’d be perfectly fine, right?

Once the blanket was off, he discovered that his chest was bare and covered with gauze, a line of red soaking into the fabric. He felt his breathing get faster, and he tried harder to get it under control. Calm thoughts, he had to think calm thoughts, the warmth of Grillby’s bar after a long day, the taste of burned spaghetti on his tongue, his brother tucking him into bed when he pretended to be asleep so he wouldn’t have to get up, but he wasn’t calming him down because his brother died and he still had that cut on his chest which means the Anomaly didn’t reset, why didn’t it reset, was this permanent? Stars, things were permanent now. Things had consequences now. His brother was dead for good.

He was hyperventilating, his ribs burning with the motion and Sans no longer trying to control it, using the searing pain to punish himself in the only way he could right now.

He miscalculated. He thought that, after the Anomaly gained as much LV as it did, it would either reset or destroy their world completely, continuing its trend of incomprehensible violence. He’d seen the data the timeline tracking sensors collected, timelines always ended when the Anomaly gained exactly 20 LV, as the one in his universe had. But neither happened. He was still alive, he was still wounded, and the world didn’t reset or disappear.

He failed, plain and simple. He failed everyone. He failed all the monsters that managed to survive the killing spree, and he failed all the ones that dusted and would now remain dust. His one job-the only one that actually mattered-was to get the Anomaly to reset and make things better. And he failed, and now his brother was gone forever.

He felt empty. Completely numb, like someone had scooped out his soul out of his chest and crushed it like a stubborn ember between their fingers. He always held onto the thought that, if his brother ever died for real, he’d cry. But he didn’t even have the decency to do that. He was just lying here, alive and breathing when there where so many others who deserved it more. Undyne, with her over-the-top heroics, wild dreams and a soft spot for those that needed protecting. Alphys, with all her stress and guilt and that spark in her eyes whenever she was excited. The lady behind the door, so sad and lonely and fighting it with laughter would now finally go home to her children. Grillby, quiet and patient for whoever needed it. All those monsters he saw every day, the ones he joked with at Grillby’s, the ones he never talked to before and now never will.

His brother, with that unwavering faith in the better of people and that beaming smile, his own little Sun smack-dab in the middle of the Underground.

He touched a fingertip to his cheek, distantly surprised at how little he felt it. His cheekbones were bone-dry. He really was the worst brother alive.

He heard a light scuffle outside the room, turning towards it in surprise, trying to see who it was that most likely bandaged him up. The scuffle got louder, approaching his room, and it sounded way too much like the familiar clicks of bone on wood. And then with a creak of old door hinges, his brother entered the room.

“…papyrus?” Sans whispered, voice shaking.

The skeleton in the doorway flinched and looked at him, surprised. “OH, YOU’RE-you’re awake,” he exclaimed, correcting his volume at Sans’ wince. It was him. Sweet stars, that was his brother’s voice, his unmistakable posture, even the way he sounded when he walked was the same, and Sans could feel tears gathering in his sockets. He never thought he’d hear his brother’s walk again.

The skeleton approached his bed carefully. It made Sans pause, stopping the pooling of tears in his sockets as he felt a sudden suspicion in the middle of his chest. He was badly injured, he didn’t understand _how_ since the world reset, so he was expecting Papyrus to throw everything in the air and run up to him, crying in relief. He did as much when Sans caught a mere cold before. His brother wasn’t doing it, though. He just slowly walked up to the bed, holding a glass of water and some cinnabunnies, and flicked the bedside lamp on, making Sans squint as the sudden light gave him a headache. He waited for the spots in his vision to disappear, trying to see his brother’s face, trying to get some reassurance to stop the feeling of his soul dropping through his chest.

The skeleton that sat down in front of him had a large gash across his left socket and his entire face was strong lines and sharp teeth, intimidating at first glance. The way he looked at Sans wasn’t with enthusiasm and kindness, but like a predator watching a strange new object, calm and curious with an edge like he could turn around and attack at a moment’s notice.

This wasn’t his brother.

The stranger in front of him was just coolly observing him, quiet and still. For a moment, Sans felt like he lost his brother all over again, the small spot of hope dying as it always did. And then, out of some sort of useless self-preservation instinct, the grief that felt like it would shatter his soul shifted into rage, the likes of which he thought he’d never feel against a fellow monster. Feeling his left socket burn, he collected his magic, ignoring the feeling of his soul painfully stretching in ways it physically couldn’t. With a shimmer of the air, a single blaster appeared above him, bathing the room in a cold blue glow.

“who the hell are you,” he growled, voice going low and as cold as his soul felt.

The tall skeleton remained immobile, looking at the blaster. Slowly, he sighed and looked back at Sans, a tired look in his sockets. The moment their eyes met, Sans shivered. Suddenly, even with his blaster and the calm the skeleton was exuding, he felt cornered.

Before he could react he felt a hand press into his neck, another grabbing his hand and pinning it to the bed by his side. Sans choked on a scream at the pain in his shoulders, a tear breaking free and rolling down his cheek. He stopped struggling as soon as he realized what happened. He knew it was futile, it would just end up with him dusting prematurely.

Noting Sans’ immediate compliance, the other skeleton bent down, quiet yet commanding. “Dispel the blaster.”

With a muffled hiss, Sans complied, feeling light-headed over the waste of magic. The other skeleton pressed harder into his neck, making his vertebrae grind together. “I will let you go, but you will not attack me. You barely survived your injuries and if you do something brainless like that again, you could re-open your wound. I can take a hit, but you’ll die if you attack. Do you understand?”

He eased up the pressure just enough for Sans to nod reluctantly, then let him go, guiding his arm back to its place, slowing down the movement as Sans winced in pain, then covered him back up with a blanket as if their altercation never happened.

Sans turned to face him. The skeleton really did sound like his brother, even looked mostly like him, but the way he talked and acted, the dark clothes he wore, even the way his default expression seemed to be a scowl instead of a happy smile, it confused him. If the world didn’t reset, his brother was still dead. This couldn’t be his brother. But then who was this monster?

He turned his head to the wall so he wouldn’t have to look at that familiar-but-not-exactly-right face, ignoring the taller monster as he tried to rearrange his pillow. He had too much to think about anyways, and his head was a giant foggy mess.

“Do you want to talk?” the other skeleton asked calmly and Sans paused. He did want answers, and his head wasn’t working well enough for him to figure things out on his own. He opened his mouth once, coughing to clear his throat and immediately regretting it as his ribs burned, then took a few shallow breaths and tried again.

“who are you?” he rasped, trying to breathe through the pain.

He heard the skeleton shift in his chair as he stared at the wall. “My name is Papyrus. And you are Sans. My brother told me you came from another world.”

Sans’ sockets widened. Of course. He ended up in another world, that’s why the reset didn’t fix him! He knew it was considered impossible to get to different universes, but with the way the Anomaly was bending the universal laws to its will it wasn’t surprising for holes to appear when there should be none. He ended up in a new world, most likely just before his own was destroyed. A universe in which Papyrus was alive.

He turned back to the skeleton, noting how calm and certain he seemed, sitting still and his face neutral. He saw movement in his peripheral vision, and looking down he saw the other skeleton subtly circling his thumbs around each other the way his brother used to, a clear nervous habit. Maybe the skeleton in front of him had more in common with his brother than just a name and looks?

“…guess I did. uh. sorry for almost blasting you, i can’t seem to think straight,” Sans said with a weak chuckle, moving his chest as little as possible. “you’re the one who bandaged me up, right? thanks.”

The other Papyrus perked up a bit, looking like he was trying hard not to smile but not able to cover the way he blushed the slightest bit. Heh, they definitely had more in common than just looks. “Of course! It is my duty as the vice-captain of the Royal Guard to assure all abruptly appearing injured monsters causing property damage are healed up until they can be questioned! I’ll…hold off on the questioning until you feel better. You should focus on healing for now!”

Sans smiled, tiredly. “nah, it’s ok. i’m all _right_ now.”

“I highly doubt that, you almost dusted! You still need plenty of-” he paused, noticing the shit-eating grin on Sans’ face. To help him along, Sans raised what was left of his left arm and wiggled his left leg. Papyrus seemed taken aback. “Was that a pun?”

Sans just smiled wider, making the other Papyrus stare in bewildered, awestruck disgust. “I can’t fucking believe this. You-you really are like my brother. Oh my God. This is either the worst or the best thing that’s ever happened to me.”

Sans shuddered in laughter, trying to keep it silent at risk of severe pain. Wow. Even the mock outrage was similar. It was like his brother wasn’t even gone.

…He should stop kidding himself like this. His brother was dead for good. He needed to stop acting like it was just a matter of time before he came back. The sooner he gave up on it, the better.

He wasn’t sure what kind of expression he was making, but the other Papyrus was giving him a worried look. Sans laughed, bitter even to his own ears. He wasn’t ready to deal with his brother’s face looking at him like that. “…listen, it’s nice chatting to you and all, but i’m kinda tired. can i go back to sleep?”

“OH! Of course, rest well! Do you want to eat something before you do? Do you need me to adjust your pillow?” The other Papyrus fretted, and Sans couldn’t stop the smile over his mother henning as he shook his head in the negative. God, this hurt. He wasn’t sure if the other Papyrus’ existence was a gift to ease his pain or a mockery of it.

The other Papyrus seemed a bit lost, like he wanted to help but didn’t know how to. It was kind of funny how he managed to stop being scary in just the few minutes he’s known him. He looked around a bit, tapping his foot in thought, then perked up and looked at Sans. “Would you like me to read something to you?! I-I’m not as good with voices as my brother, but maybe it could help you sleep?”

Sans blinked, a sort of stabbing pain in his soul. The Papyrus was giving him puppy dog eyes. “…ok. that would be nice of you.”

Papyrus smiled, wide and beaming, a surprisingly good fit to his sharp, scarred face. He ran out of the room, very quietly for a barefoot skeleton, and Sans took the moment alone to breathe. He wanted to be alone, actually. He needed to sort out what was happening, and what he would do, and how he even got here in the first place, but he also wasn’t sure if he wanted to live or not at this point so he might as well rest and heal up before he decided. He’d think more once his head cleared up and the pangs of pain he felt everywhere weren’t so distracting.

Papyrus returned soon with the book _1000 Advanced Puzzle Mechanisms_. “I thought about bringing Fluffy Bunny, but it’s very emotionally taxing and I thought this would be nice and calming. Would you prefer it anyways?”

“nah, this is fine. come on, i wanna hear it, engineering always _puzzled_ me,” Sans said, snickering at Papyrus’ angry squawk. The taller skeleton sat in his chair, cleared his throat and started reading, getting into the more advanced bouts of engineering and explaining them as well as correcting the occasional mistakes in the book.

Sans realized the bedtime reading was actually a good idea. His already low concentration was focused on the words instead of his memories or his worries, leaving his mind calm and softly buzzing. When his sockets slowly closed, he pretended this was all a dream. He imagined the mostly quiet voice was his brother’s, he imagined the blankets smelled like ketchup, he imagined tomorrow he would wake up to his brother singing off-tune, cooking in the kitchen.

Soon he was drifting off, and he was only half-aware of a hand stroking his forehead before he fell asleep.

**Notes for the Chapter:**

> Damn I forgot in the last chapter, you can find me on my tumblr [here](http://captain-shitpost.tumblr.com/).  
> Also, whenever I think of Sans slamming into that bar table, [all I can think of is this video](https://www.youtube.com/watch?v=PDOZ_hyu7Lo&index=5&list=FLq5VcacP2PNiPAlk_dW-ZlA).
> 
> It's a short one, since if I made it as long as I was planning y'all would have to wait 2 more weeks for it. And ffs I'm writing this instead of studying for my test on monday. How do I even pass my classes. What tf am I doing with my life. Life is an endless abyss. The only thing still making me happy is [this damn song](https://www.youtube.com/watch?v=DJztXj2GPfk).  
> 

**Author's Note:**

> "She was the most beautiful, complicated thing I'd ever seen. A tangled mess of silky string. And all I wanted of life, was to sit down cross-legged and untie her knots."
> 
> This fic is mostly an exploration of mental/physical recovery after a Genocide run, established relationships, how a relationship becoming poly changes things and also an exploration of sexuality. Fuck that sounds pretentious, there will be smut and threesomes lol 
> 
> I got the idea for this fic reading Mercy_Run's [Karmic Retribution](http://archiveofourown.org/works/8255036/chapters/18915266). Also I was thirsty af for Kustard after writing Bright Eyes. Also I always wanted to write a poly relationship. Also I want fluffy spicy Underfell fontcest. Also I'm shitposting.


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